1. Technical Field
The present invention relates to a toner for electrostatic image development, a toner cartridge, a process cartridge and an image forming apparatus.
2. Related Art
The image forming apparatus in the so-called xerographic system is provided with an image holding member (hereinafter referred to sometimes as “photoreceptor”), a charging device, an exposure device, a developing device, a transfer device and a fixing device and forms an image by an electrophotographic system using these devices. In recent years, an image forming apparatus in the xerographic system attains a higher speed, high image qualities and a long lifetime by technical development of the member and the system.
For achieving high image qualities, it is necessary that a fine latent image formed in an optical system is used to faithfully produce an image, and for improvement of faithful reproducibility of a fine latent image, it is attempted to reduce the diameter of a toner. From the viewpoint of higher speed and low energy consumption, an electrophotographic toner capable of fixing in a shorter time and an electrophotographic toner capable of fixing at lower temperature, that is, an electrophotographic toner capable of fixing with low fixing energy is demanded. To lower the fixing energy of the toner, a toner resin (binder resin) having a relatively low glass transition temperature is used or a plasticizer is added, and it is desired that while aggregation of toner particles is inhibited, the fixing energy is reduced.
Generally when the toner undergoes stress in a developing machine etc., external additives adhered to the surface of the toner are released or buried, thus increasing the area where the external additives are not present on the surface of a toner particle, and as a result, the non-electrostatic adhesion of the toner tends to increase. This tendency is more significant in toners and toner materials fixable with low energy, and there is demand for effectively preventing the clogging of a carrier device and a recovery device with toners, caused by aggregation of toner particles, adhesion of toner particles to the devices, and reduction in the fluidity of a toner particle powder layer.